The planned research is a systematic laboratory and clinical study of nonverbal facial behavior related to three types of acute dental pain. These three pain types--pain induced by electrical tooth pulp stimulation in the laboratory, naturally-arising pathologic pain of dental infection, and operative pain due to oral surgery--differ in origin and time course and in whether their source may be identified with dental procedures. The aims of this study are to systematically describe, quantify and compare facial behaviors of pain and negative affect accompanying these pain types; and to ascertain the relationship between measurable facial behaviors of pain and 1) verbal pain report, 2) physiological correlates of pain, and 3) certain individual characteristics including anxiety level, pain sensitivity, age and sex. Videotape records of facial behavior will be collected under comparable experimental conditions in the laboratory and in two clinical treatment settings. Clinical treatment for pathologic pain and oral surgery procedures will also be videotaped. Video records will be systematically sampled; samples will be coded using the highly reliable Facial Action Coding System, a system based on identifiable movements of individual facial muscles. Data derived from this coding process will be compiled into measures of the frequency, intensity and duration of facial expressions of pain and negative affect. These measures will be compared with subjective pain report as measured by visual analogue scales and category scales for reporting sensory, cognitive and affective dimensions of pain, and with pain response as indicated by brain evoked potentials or cortical power spectrum analysis of the EEG. Analyses of the relationship of facial expression measures to individual measures of general and specific anxiety and dental fear, behavioral response measures (absolute sensation threshold, pain threshold) and demographic characteristics will also be performed. Specific hypotheses regarding behavioral differences across pain types will be tested. This work presents the possibility of developing new quantitative measures of the assessment of clincal pain states. The final component of the proposed research is an investigation of dentists' sensitivity to patients' verbal pain report and nonverbal pain behavior.